544 THE CAUSES OF EVOLUTION 



convincing by itself. In conclusion, it should be said that there 

 are certain biologists who find some of the modern experimental 

 evidence more satisfactory than is indicated by the foregoing 

 criticisms. The problem is a complex one, and evidence of the 

 inheritance of characteristics acquired by use or disuse and under 

 the influence of environment may be discovered at any time. 

 The old Scotch verdict of " not proven " is a good one in such a 

 case; yet the long-continued failure to secure evidence for the 

 inheritance of acquired characteristics counts heavily against the 

 theory. 



The Darwinian Theory of Natural Selection or the Survival of the 



Fittest 



Historical. — The ideas of Lamarck regarding the fact of evolu- 

 tion and its causes attained considerable vogue during the early 

 nineteenth century, but were apparently overthrown by Cuvier 

 (1769-1832, cf. Fig. 260, p. 496), the greatest zoologist of his day, 

 who opposed the idea of evolution. In 1830, the year following 

 Lamarck's death, a debate was held before the French Academy, 

 in which St. Hilaire (1772-1844) upheld the Lamarckian doctrines 

 against Cuvier and in which the latter was victorious. Although 

 Cuvier was not an evolutionist he was forced to admit the differ- 

 ence between the animals of the past and those of the present, a 

 difference which could not exist if animals were originally created 

 as they are now and had not changed. Accordingly, he espoused 

 the Doctrine of Cataclysms, which assumes not one but a series of 

 creations, each followed by a " cataclysm " which destroyed all hfe. 

 By supposing that each creation was on a higher level than the 

 preceding one, it was possible to explain the succession of types 

 appearing in the fossil record. This theory was exploded by the 

 geologists, principally Lyell (1797-1875, cf. Fig. 261, p. 496), who 

 showed that there had been no cataclysms. The date of publi- 

 cation of Lyell's famous " Principles of Geology " coincides with the 

 debate in which Cuvier was supposed to have overthrown Evolu- 

 tion. The period from 1830 to 1859, during which Darwin was 

 engaged in the work that was summarized in his famous volume, 

 " The Origin of Species," was one of quiescence for the evolution- 

 ary theory. There was much popular and scientific interest, how- 

 ever, as shown by the large sales of a popular work by Robert 



